How do octopuses change their color?
By Devansh Sharma
Have you ever wondered how octopuses change color and are able to camouflage with their surroundings so well? Octopuses, squids, and cuttlefish are some of the only animals in the world that can change the color of their skin in the blink of an eye. These animals are classified as cephalopods.
Octopuses have thousands of color-changing cells called chromatophores just below the surface of their skin. The center of each chromatophore contains an elastic, balloon-like sac full of pigment; these sacs can contain black, brown, orange, or even yellow colored pigment. The octopus has nerves and muscles in its body that control whether the sac is expanded or contracted. When the sac expands, the color is more visible, since the pigment-filled sac is bigger. When the sac contracts, the color is less visible, since the sac is now smaller. They also have cells that reflect light, creating iridescent greens, blues, silvers, and golds (meaning the color changes depending on the angle you look at it from!), as well as cells that mirror the colors of the environment, making the octopus almost invisible.
But why would octopuses want to change the color of their skin? The main reason is to hide from predators, or animals that would eat them. Because octopuses have such soft bodies, they are especially vulnerable to predators, but by camouflaging with their environment and appearing invisible, they can easily hide from and escape them! In fact, octopuses are even able to change the very texture of their skin, making it rough like a rock or spiky like a coral. They do this by controlling the size of projections on their skin, and can make their skin bumpy, spiky, or smooth!
Besides changing the color of their skin, octopuses can also spray ink in order to distract and run away from predators. Since their bodies are so soft and flexible, they can even get through any hole that their beak can get through!
Can you identify the octopus in the image above? Notice how well it camouflages with its surroundings, even including small circles of brighter color on its skin to match the roughness of the rock.